Rotor with spaced large shredding blades cooperating with toothed stator



Nov. 4, 1958 R. B. HONEYMAN 2,858,990

ROTOR WITH SPACED LARGE SHREDDING BLADES COOPERATING WITH TOOTHED STATORFiled July 29, 1957 3 Sheets-Sheet 1 INVENTOR.

ROBE RT BLAKE LEY V HONEYMAN ATTORNEY,

Nov. 4, 1958 v R. B. HONEYMAN 2,858,990

ROTOR WITH SPACED LARGE SHREDDING BLADES COOPERATING WITH TOOTHED STATOR3 Sheets-Sheet .2

Filed July 29, 1957 INVENTOR. ROBERT BLAKE LEY HONEYMAN ATTOR N EYUnited States Patent C) ROTOR WITH SPACED LARGE SHREDDING COQPERATINGWITH TOOTHED Robert B. Honeyman, Portland,,0reg., assignor to MordenMachines Company, Portland, reg., a corporation of OregonApplicationJuly 29, 1957,,Serial No. 674,751 4 Claims. ((312.241-260)must be broken up, shredded and slushed, and the fibers in= the-materialshould:be:subj'ected to'a certainamount of refiningaction:

The invention relates specifically to" the particular type ofmachine-for shreddingi and treating" fibrous material to be-usedin papermanufacture-as described in; U. St Patent No. 2,654,294 to C.- W.Morden, issued unden'date of Qctober: 63,1953, andentitledPulp Shreddingand Treat ing Machine, and reference should be made to: this:

earlier patentv for a. full: understanding of the present invention.

In-the device of theabove mentioned patent, Non.

2,654,294, the shredding and treatingofthe'fibrous-pul'p material areaccomplished by means of arrot'or operating" in conjunction with astationary impingementring, the:

stationary'ring haV-inga comically-shaped attritioning sur-' face, therotor having peripheral blades which move over this stationaryattritioning; surface, and the under sides of the rotor bladesso-located; as to liein a conical surface capable; of matingwith theattritioning surface ofthe stationary ring.

The blades of the rotor, in thedevice of the above mentioned patent, aredesigned to serve the double purpose of impinging material stationaryring andof cooperatingwith the stationary ring in subjecting the fibrousmaterial to an attritioning action between the rotatingblades and thestationary ringsurface, and, under optimum conditions, this doublepurpose is accomplished toa large extent by the device described in thepatent. In-such a-device the blades on the rotating rotor must ofnecessityrbe fairly close together in order to perform the desiredattritioning action in the short lengthof time during which the fibrousmaterialis-in contact with the conicalor attritioni-ng surface ofthe'stationary ring, and in consequence the pieces of the fibrousmaterial must firstof. all be small enough to pass down between theblades of the rotor so as-to reach the attritioning surface on thestationary-ring; the, material to be'trea-tedincludesa considerableamount of moderately large pieces or slabsof'such fibrous mate rial, asis frequently the case, these larger pieces or slabs.

will collect on the rotor, or bridge over porarily until they aresufiiciently broken this interval they. actas ablock to the smallerparticles of material and act as an impediment performance of theintended function of the has beenfound that this condition may exist tosuch an extent temporarily thatthe circulation'set up' through theblades of the rotor will be reducedlargely to water and the rotor,temconsequently during suchtemporary interval the machineoperation isfar from:being eflicient.

of such materiall for use in the manufacture of paper'and relatedproducts, the materialagainst the conical surface of the- However, whenup, and during in the proper: machine. It

Various attemptshave been made to achieve more efii'= cient operation ofthe machine by relieving such condi t-ions and reducing the-timerequired for the breaking up of such largerpiecesof fibrous material,including increasing therotor speed. However, these have not proved asatisfactory solution to the problem, and furthermore a considerableincrease in the speed at which the-rotor is driven results in the use ofa greater amount of power at increased ratio'of power consumption to'rotor speed.

An object of the present inventionaccordingly is to facilitate andhasten the breaking up of larger pieces of slabs of material, in a pulpshredding and treating maa chine of the type mentioned, withoutrequiring any very extensive changes in the overall constructionofsuch'ma chine, and without even-changing the number or spacing of therotor blades which are considered most desirable for the particularmachine size or given installation, and

withoutvarying the important and necessary cooperation" tive circulationof the material through the'rotor blades andover the attritioning faceof the stationary ring.

These objects and' otherincidental advantages are attainedbychangingsome of the rotor blades to make them-extend up'beyond the top edges ofamajorityof the blades=onthe rotor so as to encounter'the-l'arger piecesor bundles of fibrous material before these larger pieces" are ablet'o'c ollect-to such extent as'toblock the passage of material down betweenthe rotor blades te-th'e attri tioning ring, but without making anychange in the size orposition of the'under sides of the higher blades"or any changes in the spacing between the blades, andby'other' specificconstruction features as hereinaftenmentionedl This improved rotorconstruction, or rotor blade" construction, of the presentinvention,will be described and explained briefly with reference to theaccompanying drawings.

In the drawings:

Figure 1 is an elevation of the improved rotor shown in its operationrelationship with the stationary attrition'-. ing'ring of the pulpshredding and treating machine;

Figure 2 is a corresponding elevation'of the stationary ring by itself,for the purpose of making the other figures clearer;

Figure 3 is a section through the improved rotor and stationary ringtaken-on the line 3-3 of Figure 1;

Figure 4 is a fragmentary section through the rotorwithoutthe stationaryattritioning ring, taken on the line 44 of Figure 1, showing one of thestandard blades of the rotor in elevation;

Figure 5 is a fragmentary section through the rotor without theattritioning ring, taken on line' 5-5'of Figure 1; showing one'of thespecial blades of the rotor in side elevation;

Figure 6' is'an outer end view of one of the standard bladessonthe rotortaken onthe line indicated at 6 6 inFigure l;

Figure 7 is a corresponding end view, drawn tothe same scale as Figure6, of the outer end of oneof' the special bladeson the'rotor taken onthe line indicated at 77 in Figure-1;

Figure 8 is a fragmentary side elevation of the rotor taken online;8'--8 ofFigure l, with the stationary attri tioning-v ringomitte'dxfor the sake of clarity, showing one of the standardtblades;and

Figure 9'is a-similar fragmentary side elevation of the totor taken online 9--9 of Figure 1 showing one of the special blades.

Referring first to Figures 1 and 3, the rotor, indicated as a whole bythe reference character 10, has a front, substantially conical, ordome-shaped, face with a series of peripheral blades. Preferably, butnot necessarily, the rotor comprises a main central integral casting 11(Figure 3) having a rearwardly-extending central boss 12 formed with atapered bore to accommodate the tapered end of the driven rotor shaft13, to which the rotor is keyed, and having a dome-shaped nut 14,secured in place on the end of the rotor shaft and in the body portion11, which completes the conical or dome-shaped rotor surface. Alsopreferably the blades of the rotor are cast integral with an annularbase or ring 15 which is then mounted in a peripheral recess 16 in themain casting 11 and secured in place on the rotor body by suitablescrews.

The composite rotor preferably, but not necessarily, is

mounted in the side of the tank containing the fibrous material to betreated, as described in U. S. Patent No. 2,654,294, and thus rotates ina vertical plane, with the conical or drome-shaped front face of therotor facing the interior of the tank. A stationary impingement andattritioning ring 17 surrounds the rotor and is secured to a housingwhich in turn is mounted to the wall of the tank, a portion of thehousing being indicated at 18 in Figure 3 and a portion of the tankbeing indicated at 18'. This stationary ring 17 has a frusto-conicalattritioning surface 19 (see also Figure 2) which is inclined at anangle (preferably of approximately 45) with respect to the plane ofrotation of the rotor. The attritioning surface is formed with a seriesof radially-extending rectangular grooves 20, thus forming radial teethor attritioning bars between the grooves of the attritioning surface 19.

The rotor blades extend beyond the rotor periphery to the periphery. ofthe attritioning surface 19 of the stationary ring, and the under sidesof the blades lie in a. frusto-conieal surface capable of mating withthe attritioning surface 19 of the stationary ring. Means (not shown) isprovided for adjusting the rotor shaft 13 to a limited extent in anaxial direction and thereby adjusting the clearance between the bladesand the attritioning sur face 19 of the stationary ring.

The rotor blades, instead of being all the same size, as has beencustomary heretofore, are of two sizes, a few of the blades having agreater height than the others. The blades, however, are all of the samewidth and the spacing is the same between all the blades. rotor shown inFigure l as an example, there are twentyseven blades. Three of theseblades, indicated by the reference character 21, are higher than theothers or the standard blades 22. The higher blades 21 of the set arespaced equal distances from each other, thus, in this instancebeingspaced 120 apart. The difference in height between the higher blades 21and the other blades 22 is shown clearly in Figures 3, 4 and 5.

The under sides of all the blades are identical in size and shape. Theunder side of each blade has an open central channel 23 which extends tothe outer end of the blade. Thus all the blades are prong-like, with theunder side of each blade having spaced surfaces, and as these prong-likeblades move closely over the attritioning surface 19 of the stationary.ring they perform a desired treating action on the pulp fibers of thefibrous material which has been impinged against the stationary ring bythe rotation of the rotor.

As apparent from Figure 1, all the rotor blades extend obliquely awayfrom the direction of rotation of the rotor, the direction of rotationbeing clockwise as viewed in Figure 1 and as indicated by the arrow x.Also the leading face of each blade, that is the lateral side of theblade facing in the direction of rotation of the rotor, extends in aplane sloping obliquely from the plane of Thus, in the rotation of therotor, while the trailing face or other lateral side of each bladeextends in a plane substantially perpendicular to the plane of rotationof the rotor. Thus the leading face 24 (Figures 7 and 9) of each of thehigher blades 21, and the leading face 25 (Figures 6 and 8) of each ofthe standard blades 22 extends in a plane sloping obliquely with respectto the plane of rotation of the rotor while the trailing face 26 of eachof the higher blades and the corresponding trailing face 27 of each ofthe standard blades extends in a plane substantially perpendicular tothe plane of rotation of the rotor.

The top ridges 28 of the standard blades 22 (Figures 3 and 4) lie mostlyin a frusto-conical surface sloping outwardly and upwardly with respectto the plane of rotation of the rotor, but sloping at a slightly lessangle than the under side faces of the blades, as shown in Figure 3, andthus sloping at a slightly less angle than the attritioning surface ofthe stationary ring. Similarly the top ridges 29 of the higher blades 21(Figures 3 and 5) lie in a frusto-conical surface which hasapproximately the same angularity with respect to the plane of rotationof the rotor as the frusto-conical surface containing the top ridges 28of the standard blades.

The top ridges of all the blades begins at approximately the same radialdistance from the axis of rotation of the rotor, starting from pointslocated substantially on a common circle on the face of the rotor. Theridges 28 of the standard blades 22 have a greater extent of curvatureat their start from the rotor face, as shown at 28 in Figure 4, than theridges 29 of the higher blades 21, as'

shown at 29' in Figure 5.

The rotation of the rotor causes the fibrous material, engaged by therotor blades, to be thrown outwardly from the rotor axis, but thisresults in a considerable portion of such engaged material beingimpinged against the frusto-conical surface of the stationary ring. Theangularity of this ring surface (preferably approximately 45 with theplane of rotation of the rotor causes the material impinged against thissurface to be momentarily restrained, and during this time the materialis subjected to an attritioning action between the under sides of theblades and the frusto-conical surface of the stationary ring with itsradially extending bars and grooves. After this brief restraint andattritioning action the material is discharged peripherally by therapidly moving blades for recirculation.

When pieces of material, small enough to pass down between the blades tothe frusto-conical surface of the stationary ring, are too large to passbetween the under sides of the blades and the ring surface, theobliquelysloping leading faces of the blades urge such pieces upwardlyand outwardly over the ring surface without forcing them in between theunder sides of the blades and the ring. The impingement of these piecesagainst the ring surface will nevertheless tend to break them up orreduce their size, so that, after a sufficient amount of recirculation,the fibrous material from such pieces will finally receive the desiredattritioning action between the blades and the frusto-conical surface ofthe stationary ring. Any foreign particles, such as tramp metal, whichmay inadvertently have been deposited in the tank with the fibrousmaterial, will also be thrown off from the ring surface by the leadingfaces of the blades, thus reducing to a minimum the damage to thetreating machine by such foreign particles.

As previously mentioned, one of the problems encountered with theoperation of the pulp shredding and treating machine of U. S. Patent No.2,654,294 has been the fact that, in many instances, larger slabs ormasses of fibrous material, being too large to pass down between therotor blades to the stationary ring, collect on or over the rotor,impeding the normal passage to the attritioning ring and retarding theproper circulation of material in thrown off from the rotor the tank.However, it has been found that the substitution of the higher blades 21for somfof the standard blades in the improved rotor prevents suchcondition developing and that pieces of the fibrous material which aretoo' large to reach' the attritioning ring at first are subjected torepeated impact by the higher blades with the result that they are-either immediately broken up sufiiciently by the higher :blades toenablelthe :reduced smaller particles to pass down to the ring," or elseare by the higher blades and in this way caused to be recirculated untilsuch time as repeated impact by the higher blades will break up theselarger pieces sufliciently. his recirculation Ofithelarger pieces,caused by the "higher blades, also has "theadded advantage of increasingthe turbulence and circulation of all of the material in the tank and atthe same time of heeping the passageways between the blades to thestationary ring open. Furthermore, this desirable increased turbulenceand circulation of the material in the tank is attained Without havingto increase rotor speed and with only a minimum increase in powerrequired.

Smce spacing between all the blades is the same, and since the higherblades are no wider than the standard blades, the operation of themachine under optimum conditions, in which there would be no pieces ofmaterial too large to take the normal prescribed course to thefrusto-conical attritioning surface of the stationary ring, is notrendered less efiicient or modified in any way by the presence of-thehigher blades. However, since such optimum conditions seldom exist, andsince generally there will be some pieces of material at the start ofthe machine operation which are too large to follow such normal course,the higher blades make it possible for these larger pieces to becontrolled and handled, and consequently increase the overall machine.

For the purpose of this description the rotor has been illustrated asequipped with a total of twenty-seven blades, including three higherblades. While rotors with this number and arrangement of blades haveproved very satisfactory and efficient, the invention is not to beconsidered as limited to a rotor having any particular number of bladesor any particular number of higher blades. Thus, for example, under someconditions it might be preferred to have four of the higher blades onthe rotor, and therefore spaced 90 apart, or more than four, or it mightbe suflicient to have only two of the higher blades. Similarly, ofcourse, the number, and therefore the spacing, of all the blades on therotor can be varied to suit diiferent conditions of operation. It isessential, however, in the carrying out of this invention, thatthenumber of the higher blades be considerably less than the number of thestandard blades on the rotor, that the higher blades be spacedequidistant from each other, and preferably also that the under sides ofthe higher blades and of the standard blades be identical.

I claim:

1. In a pulp shredding and treating machine of the character describedwherein a rotor is surrounded by a stationary ring having afrusto-conical attritioning surface and a plurality of blades on therotor extend beyond the operating efliciency of the periphery of therotor over the attritioning surface of the v stationary ring and theunder sides of the blades lie in a fmsto-conical surface capable ofmating with the attritioning surface of the stationary ring, theimprovement in the rotor which includes having a few of said blades madeof greater height than the other blades, but with the under sides ofsaid higher blades lying in the same frusto-conical surface as the undersides of said other blades, said higher blades equally spaced from eachother, the top edges of said higher blades extending in a frustoconicalsurface inclined at an angle with the plane of rotation of the rotor andthe top edges of all of said blades beginning on said rotor at pointslocated substantially on a common circle concentric with the rotor axis,whereby,

with the rotation of said rotor, said higher blades will encounterlarger pieces of the material being treated in -said machine beforesaid-larger pieces reach said other blades on said rotor andthereby-reduce the tendency of said larger pieces to impede the properfunctioning of the machine.

2. In apulpshredding and treating machine including a rotor surroundedby a stationary ring having a frustoconical attritioning surface and aplurality of blades on the rotor extending beyond the periphery of therotor over the attritioning surface of the stationary rin with the undersides .of the blades lying in a frus'to-conica'l surface capableurinatin with the attritioning surface of the stationary ring, theimprovement in the rotor which comprises having a fewof said blades madeof greater height than the other blades, but with the under sides ofsaid higher blades lying in the same frusto-conical surface as the undersides of said other blades, the under sides of said higher blades beingidentical in shape and size with the under sides of said other blades,said higher blades equally spaced from each other, the top edges of saidother blades extending in a frusto-conical surface inclined at a lessangle with the plane of rotation of said rotor than the under sides ofsaid blades, and the top edges of said higher blades extending in afrusto-conical surface inclined at substantially the same angle withsaid plane of rotation of the rotor as the top edges of said otherblades, whereby, with the rotation of said rotor, said higher bladeswill encounter larger pieces of the material being treated in saidmachine before said larger pieces reach said other blades on said rotorand thereby reduce the tendency of said larger pieces to impede theproper functioning of the machine.

3. In a pulp shredding and treating machine wherein a rotor issurrounded by a stationary ring having a frustoconical attritioningsurface and a plurality of prong-like blades on the rotor extend beyondthe rotor periphery over the attritioning surface of the stationary ringand the under sides of the blades lie in a frusto-conical surfacecapable of mating with the attritioning surface of the stationary ring,the improvement which comprises having a few of said blades made ofgreater height than the other blades, but with the under sides of saidhigher blades lying in the same frusto-conical surface as the undersides of said other blades, the under sides of said higher blades beingidentical in shape and size with the under sides of said other blades,all of said blades being equally spaced on the periphery of said rotor,said higher blades equally spaced from each other, the lateral side ofeach of said higher blades facing in the direction of rotation of saidrotor extending in a plane oblique to the plane of rotation of saidrotor, the opposite trailing side of each of said higher bladesextending in a plane substantially perpendicular to said plane ofrotation, the top edges of said higher blades extending in afrusto-conical surface inclined at an angle with said plane of rotation,and the top edges of all of said blades beginning on said rotor atpoints located substantially on a common circle concentric with therotor axis, whereby, with the rotation of said rotor, said higher bladeswill encounter larger pieces of material being treated in said machinebefore said larger pieces reach said other blades on said rotor andthereby reduce the tendency of said larger pieces to impede the properfunctioning of the machine.

4. In a pulp shredding and treating machine of the character describedincluding a rotor surrounded by a stationary ring having afrusto-conical attritioning surface and a plurality of prong-like bladeson the rotor extending beyond the periphery of the rotor over theattritioning surface of the stationary ring with the under sides of theblades lying in a frusto-conical surface capable of mating with theattritioning surface of the stationary ring, the improvement in therotor which consists in having a few of said blades made of greaterheight than the other blades, but with the under sides of said higherblades lying 7 in the same frusto-conical surface as the under sides ofsaid other blades, the under sides of said higher blades being identicalin shape and size with the under sides of said other blades, all of saidblades being equally spaced on the periphery of said rotor, said higherblades equally spaced from each other, the lateral side of each blade'facing in the direction of rotation of said rotor extending in a planeoblique to the plane of rotation of said rotor, the opposite trailingside of each blade extending in a plane substantially perpendicular tosaid plane of rotation, the top edges of said other blades extending ina frustoconical surface, and the top edges of said higher bladesextending in a frusto-conical surface inclined at approximately the sameangle with said plane of rotation as the top edges of said other blades,and the top edges of all of said blades beginning on said rotor atpoints located substantially on a common circle concentric with therotor axis, whereby, with the rotation of said rotor, said higher bladeswill encounter larger pieces of material being treated in said machinebefore said larger pieces reach said other blades on said rotor andthereby reduce the tendency of said larger pieces to impede the properfunctioning of the machine.

References Cited in the file of this patent UNITED STATES PATENTS

